1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus capable of being simple to manufacture or repair and reducing cost.
2. Description of the Related Art
FIG. 1 is a side view illustrating a structure of an image forming apparatus using a related ring conductor, FIG. 2 is a schematic perspective view illustrating a related image forming element according to a related art, and FIG. 3 is an enlarged cross-sectional view illustrating a portion of the circumferential wall of the image forming element according to the related art. The image forming element shown in FIGS. 2 and 3 is disclosed in U.S. Pat. No. 6,014,157 by reference.
Referring to FIGS. 1 through 3, the related image forming apparatus includes a toner supply unit 40, an image forming element 10, a magnetic cutter 50 separating a part of toner 1 adsorbed to the image forming element 10, and a toner return unit 60 which returns the toner 1 separated by the magnetic cutter 50 to the toner supply unit 40. The toner supply unit 40 supplies the toner by using a toner supply roller 42 from a toner storage 41. The image forming element 10 includes an image drum 12 and a plurality of ring electrodes 14 disposed on the image drum 12. Also, a control unit 16 is installed inside of the image drum to individually apply a voltage. The magnetic cutter 50 capable of separating the toner 1 adsorbed to the image forming element 10 is provided outside of the image drum 12.
When a voltage is not applied to the ring electrodes 14, the magnetic cutter 50 may separate the toner 1 adsorbed to the image forming element 10. However, when a voltage is applied to the ring electrodes 14, the toner 1 is not returned to the toner supply unit 40 by the magnetic cutter 50 and is transferred to an image transfer unit 70. The toner 1 transferred to the image transfer unit 70 is transferred to a printing paper and the printing paper is heated, thereby fixing the toner 1 to the printing paper.
However, there are problems of being difficult and very costly to manufacture or repair the image forming element 10. For example, to manufacture the related image forming element 10, grooves are cut into the outer circumferential surface of the drum body to have a pitch of approximately 40 μm and a width of approximately 20 μm, in which a conductive material is filled, and a hole is formed on the control unit and ring electrodes to electrically connect them. As a result, printers made using the related image forming method and apparatus have a high cost making popular acceptance for such printers difficult to achieve.